1921 Koester Bakery Stars of Baseball New York Giants/Yankees, Lot #80003
1921 Baseball History - This Great Game
Daily News Front Page October 5, 1921 by New York Daily News Archive
1921: The Yankees, the Giants, & the Battle for Baseball Supremacy in New York' - Los Angeles Times
GoingDeep: Phil Douglas' battle with baseball in 1922 derailed a stellar career
SABR Century: 1921 Rise of the Yankees – Society for American Baseball Research
Pivotal World Series Plays
1921 World Series - Wikipedia
The History of Baseball: A Series About The Myths Some Writers Cling Too and Stories and Players That Don't Get Celebrated, by David B Morris
August 27, 1921: Giants beat Pirates 3-1 to complete 5-game sweep – Society for American Baseball Research
SABR Century: 1921 All-NYC World Series – Society for American Baseball Research